1. Field of the Invention
The invention relates to an ink duct for tubular styluses.
2. Description of the Prior Art
It is customary, for tubular styluses, to employ spiral compensating systems, which have the disadvantage that in the case of an ink storage volume in excess of 1.5 cm.sup.3 the spiral system reacts too sluggishly to temperature fluctuations and undesirable drop formation occurs at the tip of the writing tube.
German Offenlegungsschrift No. 3,205,800 discloses an ink duct system for ink drawing implements with a spiral, labyrinthine ink compensation means, or provided with longitudinal chambers, with axially movable drop weight with cleaning wire and writing tube, in which the ink compensation means has in its internal bore, or the drop weight on its envelope surface, at least one capillary groove multiply subdivided in the longitudinal direction, which extends as a relatively low-capillary ventilation capillary from the connecting tube to a narrower air control point located in the lower half of the ink compensating means and is passed below ink control point as a high-capillary connecting capillary to the writing-tube, whilst an axially oriented ink capillary is in communication with the air control point. The ink duct system has no lamellae, but a spiral system.
The documents of German Utility Design No. 7, 633,429 relates to a writing tip for tubular writing implements with drop weight and securing element, in which an optionally spring-like connecting element, which is provided between drop weight and securing element, is constructed integrally with, or otherwise firmly connected to, both the parts.
The aim of the invention is to propose an ink duct system which reliably controls a volme of ink in excess of approximately 1.5 cm.sup.3, such as is demanded for a non-refillable drawing implement for example, and therefore reacts more sensitively to temperature fluctuations and nevertheless embodies the advantage of vibration resistance in the spiral system.